Method of forming coils for electrical apparatus.



No. 744,013. PATENTED Nov. 17, 1903.

E. L. AIKEN. 7 METHOD OF FORMING cons FOR ELECTRICAL APPARATUS.APPLICATION FILED DEG. 5, 1898. N0 MODEL. 3 SEEET8SHEET I.

Hal. 1 1 @D 1 ca 1 a I [ll 1 v I j WI NEEsEEQ v I [WEN-ft] 3Q w R I 7Edward .fiikefl WW ,1}? VA No. 744,018. PATENTBD NOV. 17, 1903.

E. L. AIKEN. METHOD OF FORMING GOILS FOR ELECTRICAL APPARATUS.

APPLICATION FILED DEG. 5, 1898. NO MODEL. 3 SHEETS-SHEET 2.

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PATENTEDNOV. 17, 1903.

3. AIKEN. METHOD OF FORMING GOILSPOR ELECTRICAL APPARATUS.

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N0 MODEL.

APPLICATION FILED DEC. 5, 1898.

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UNITED STATES a Fatented. hlovember l7,' 1903 PATENT; OFFICE.

EDWARD L. AIKEN, OF SOHENEOTADY, NEW YORK, ASSIGNOR .TO THE GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ME'l'HOD OF FORMING COILS FOR ELECTRICAL APPARATUS.

SPECIFICATION forming part of Letters Patent No. 744,018, dated November17, 1903. Application filed December 5, 1898. fierial No- 698,243. (Nomodel.) I

method of providing magnetic polepieces with the required ampere-turnshas been heretofore to wind the cores of such polepieces with a largenumber of convolutions of round wire covered with fibrous insulation andexcite said pole-pieces by a relatively small electric current. Thespace occupied by the fibrous insulation and the space left unoccupiedbetween individual convolutions is so considerable as to render thepole-pieces very bulky, and, moreover,prevents the radiation of heatfrom the cores.

The object of my invention is to provide such pole-pieces withconducting-coils, in which fiat non-fibrous insulation, such as mica, isused between the contiguous sides of the convolutions, and wherein themetal of such conductors extends uninterrupted from the cores to theoutside of the coils, whereby a metallic conduction of the heat from thecores is provided.

My invention consists in a coil made by bendingarelatively wide and thinstrip of conducting material edgewise into a helix without reduction ofcross-sectional area and in the method of making said coils.

The particular means which I employ for carrying out the method in themanufacture of my improved coils is illustrated in the accompanyingdrawings, and in which- Figure 1 represents an engine-lathe of ordinaryconstruction with a coil in process of winding thereon. Fig. 2 is a sideelevation, partly in section, of a part of the device shown in Fig. 1,here drawn upon an enlarged scale. Fig. 3 is an end elevation, partly insection, of the parts shown in Fig. 2, taken on the line 3 3. Fig. 4. isa plan, partly in section, of the arrangement shown in Figs. 2 and 3 forconfining the strip while it is being wound. Fig. 5 is a plan of a partof the mandrel, with a coil partly wound thereon. Fig. 6 is a section oftwo turns of the coil, drawn upon an I enlarged scale and showing thecoil just after leaving the mandrel. Fig. 7 is a perspective of thecoil, partly broken away, as it is taken from the mandrel. Fig. 8 is aplan, partly broken away, of the die in which the coil is pressed intoshape. Fig. 9 is an end elevation of the parts shown in Fig. 8. Fig. 10is a perspective of the end plate shaped to fit the coil, so that thelatter will not be distorted in the press. Fig. 11 is a perspective ofthe completed coil. Fig. 11 is a section of a single turn of theconductor at the point 7 marked 11 in Fig. 11. Fig. 11 is a similarsection at the point marked 12.

In Fig. 1, A is the bed of a lathe, boring-mill,

or other rotating mechanical structure. Of course any one of thesedevices may be used, as convenience may dictate, the essential featurebeing that it shall have sufficient power to turn the mandrel againstthe tension of the conductor being wound. Bis the usual slide-rest,which may be fed by hand, if desired, but is ordinarily pushed along theslideways by the pressure of the work against the guide carried by theslide-rest. O is the mandrel, the construction of which will be bestunderstood from Fig. 2. The other parts of the lathe are not referred tospecificallyby letter, inasmuch as their construction is well known andreadily apparent. E is the conductor, which is to be wound from the reelE.

As shown 'in Fig. 2, O is a mandrel which rotates between the centers XXv byany suitable means, such as the pius F F", connected with theface-plate of the lathe. As shown in Fig. 5, the face of the enlargedshoulder of the mandrel C is shaped as a helicoid. In this figure alsois shown a slot 0 in the shoulder, into which the bent end E of thestrip E is inserted to secure that end to the mandrel.

In Figs. 2 and 4., D is a non-rotatable ring secured to move with theslide-rest B, having a working fit with the mandrel (land adapted toslide longitudinally thereof, whereby said ring occupies positionssuccessively farther removed from the shoulder of the mandrel C, so thatthe increasing coil of the strip E on the mandrel C is clamped betweenthe shoulder of the mandrel and the ring D to assist in preventingbuckling of the strip. The ring D is secured to the slide-rest B in thefollowing manner: As shown in Fig. 2, the base-block B is carried by theslide-rest, which block extends at a tangent to the surface of themandrel O and forms a joint with the ring D by the ring being cut awayfor a portion of its width along the line of a chord tangent to theinner circumference of the ring, thus forming a flat surface which restson the block B The entire width of the ring D is not, however, cut awayin this manner, but only as far as the right-hand edge of the block 13as shown by the inner dotted line in Fig. 4, thus leaving a dependingarc or lip D, Fig. 2, which extends along the side of the block 13. Thering D is secured to the block B by bolts D Figs. 2 and 4, which passthrough the lip D into the part B. Other bolts (not shown) may pass upthrough the block B and into the ring D at the lower flat cut-awaysurface thereof. The ring D is formed with a helicoidal face opposingthe similarly-shaped face of the shoulder of the mandrel O, and thestrip E passes between these two surfaces and is wound on the mandrel.The block B and the ring D are cut away, as shown in Figs. 2 and 4, toprovide a space for the block B, which is adjusted by means of a screw Bpassing through the lip D of the ring, to force a rod or roller 12,which acts as an antifriction device, against the strip E, which passesbetween the roller hand a guide 13 bolted to the block B The strip-coilon the mandrel presses against the guide B and is securely held frombuckling between the end of the wound coil and said guide B The rod orroller 17 or its equiva lent is a very important feature of the machine,as without some such means it would be practically impossible toinitially bend a strip so thin without buckling or crimping, thethickness of said strip being only a sixth or less of the width.

Referring to Figs. 3 and 4, the operation may be described as follows:The strip E enters from the right between the ring D and the guide B andpasses beneath innermost projection of the helicoidal surface of thering, which overhangs the strip and the guide B as shown in Fig. at. Thestrip then passes in contact with the roller and is forced by thehelicoidal surface of the ring to assume the form of a helix surroundingthe mandrel 'O. The slide-rest B, which carries the part B and the ringD, is free to slide parallel to the axis of the mandrel C under thepressure of the strip E as it is being coiled.

Fig. 7 shows the coil when it is removed from the mandrel. At this timeit is cylindrical, and the section of the layers is as .shown in Fig. 6,each layer being marked E The inner edge e is shown thicker than theouter edge e, and between each layer of the coil on the outer edge isplaced a strip g, which may be of any desired material, but usually isof thick paper, the same being removed before the final insulation e isinserted. Thisis done to keep the several convolutions of the -coil inposition and inapproximately cylindrical shape for the press.

In Figs. 8 and 9, H H are the sides of the form or die in which the coilis pressed into its final shape. The dotted circle E represents thecylindrical coil as it is when first put in the press. A block I-I justfits at its ends the inner periphery of the uncompressed coil, and outerblocks h h at each end have faces curved to fit'the final shape of theends of the coil.

As it is manifest that the coil as shown in Fig. 7 will have each endprojecting beyond the helix by an amount equal to the thickness of thestrip, so that if it were pressed firmly together in this shape the endswould be distorted, I prepare rings K, such as are shown in Fig. 10, theinner surface of each of which is turned to a helix having a shoulder K,against which the end of the coil rest-s. When one of these is placedupon each end of the coil, the whole becomes a cylinder with plane ends,and in this shape it is inserted in the press. New rings are of coursenecessary for each coil, as it is manifest that at each operation theyare distorted to the shape of the coil as it leaves the die. After theparts of the die are secured in place by the bolts I I pressure isapplied to the sides of the coil in any convenient manner, and it isbroughtto the shape shownin Fig. 11. The ends of the coil are left, aswill be apparent from Fig. 8, free to move out from the block II untilthey bear against the curved blocks h h, and as the sides E of the coil(see Fig. 11) are brought from the shape shown in Fig. 7 the thickenedinner edge stretches until the strip at this part of the coil becomes ofsubstantially the same thickness throughout, as shown in Fig. 11", whileas the ends bearing againstthe blocks h h are notstretched so much theyretain to a great extent the trapezoidal cross-section shown in Fig.11". After the coil is removed from the press the paper spacing-stripsare removed from between the convolutions and permanent insulation einserted. This insulation may be of any of the well-known materialsadapted for that purpose, such as mica, rubber prepared fiber, and thelike.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. The method which consists in winding a strip of uniform thincross-section into a cylindrical helical coil wherein the surfaces ofthe strip are substantially perpendicular to the axis of the coil, andthe inner edge of the strip is thicker than the outer edge, and thencompressing the sides of the coil so that it the axis of the coil andthereafter shaping assumes an oblong shape with curved ends, saidhelical coil into the desired contour. :0 wherein the inner edges of thecoil have been In witnesswhereof I have hereunto set my stretched. handthis 3d day of December, 1898.

5 2. The method which consists in winding 21- EDWARD L. AIKEN. strip ofrelatively wide and thin cross-section Witnesses: into a helical coilwherein the flat surfaces of B. B. HULL,

the strip are substantially perpendicular to A. D. LUNT.

